No. Mark Twain is being, well, Mark Twain. That isn't to say there is nothing to what he wrote there, but he (presumably purposefully for humorous purposes) mixes cause and effect. It isn't that Sir Walter Scott's books inspired the mentality of honor that characterized the elites of the South, but that their mentality of honor disposed them to a particular appreciation of his romances, as they fit into that worldview.

It was, however, a worldview that predated Scott's works, so we can't blame him for it. Historians like Bertram Wyatt-Brown trace the impulses of Southern honor culture deep into the 18th century. Although focused more specifically on the duelists subset of that culture, it is something I've written about before here.

Seelye, John D. 2001. “Ivan Who?: A Second Look at the Other Book That Is Supposed to Have Started the Civil War.” In Finding Colonial Americas: Essays Honoring J.A. Leo Lemay, edited by Carla Mulford and David S. Shields, 415–33. University of Delaware Press.

Wyatt-Brown, Bertram. Southern Honor: Ethics and Behavior in the Old South. OUP, 1982.